1. Field of the Invention
The present invention relates to compatibilized compositions comprising a polyamide and polypropylene. It relates more particularly to compositions exhibiting an improved combination of mechanical and adhesive properties and comprising a semiaromatic polyamide and polypropylene of which at least a part is modified by grafting with a polar monomer, and optionally a fibrous reinforcing agent.
The invention also relates to adhesive composites of these compositions with other materials, generally chosen from organic synthetic polymers, cellulosic products and metals, and to shaped objects made from these composites.
2. Background of the Invention
Compositions based on polypropylene (called PP hereinafter) of which a part is modified by an unsaturated carboxylic acid or an anhydride of such an acid and also containing a polyamide (called PA hereinafter) and glass fibres as a reinforcing material have been described in patents US-A-4,404,312 (Toyo Boseki K.K.) and GB-A-1,345,747 (Mitsubishi Rayon Co.). These compositions exhibit advantageous mechanical properties such as high rigidity and impact strength.
Compositions exhibiting a synergy in certain physical properties, such as adhesiveness, are also known (U.S. Pat. No. 3,804,919 in the name of Dart Industries, Inc.). These compositions are, for example, mixtures of unmodified PP and of PP modified by reaction with glycidyl acrylate in the presence of an organic peroxide. The PPs are reinforced using glass fibres (examples).
However, it has not been possible, until now, to unite a satisfactory combination of mechanical properties and of adhesiveness properties in the same single composition.